Question

How many $P - O - P$ bonds(s) is/are present in ${H_6}{P_6}{O_{18}}$ ?

Answer 1

${H_6}{P_6}{O_{18}}$ is known as meta-phosphoric acid. Generally, the number of ${\text{P - O - P}}$ bonds in cyclic metaphosphoric acid is three. ${\text{P - O - P}}$ bonds are the bond linkages present between two phosphorus atoms and one oxygen atom.

Complete step by step answer: The general formula of metaphosphoric acids is ${\text{(HP}}{{\text{O}}_{\text{3}}}{\text{)n}}$ where n denotes the number of phosphoric acid units present in the ring. ‘n’ can be equal to three or greater than three. Metaphosphoric acids have phosphorus in the oxidation state of ${\text{ + 5}}$. It generally decomposes in water and is soluble in alcohol. It is an odorless, glassy substance.
${H_6}{P_6}{O_{18}}$ is meta-phosphoric acid . it is a corrosive inorganic , cyclic polyphosphate formed from bonded phosphoric acid units.
It has applications in biochemistry, agriculture , pharmacy and chemical research.
Structure of meta-phosphoric acid is :

As it is clear from the above representation of meta-phosphoric acid, there are three $P - O - P$ bonds.
So, the answer to the question will be three.

Additional Information:
-Meta-phosphoric acid is used by food analytics to determine the vitamins.
-The biochemistry also makes use of this compound to precipitate protein in biological liquids such as blood and urine.
-For vets, it can be used to check the urea in cattle blood.
-It can also be used as an additive in the production of diagnostic test strips for the pharmaceutical industry.
-Metaphosphoric acid is used to prevent oxidation of reduced glutathione.

Note: Meta-phosphoric acid or ${H_6}{P_6}{O_{18}}$ has various uses in various fields. The number of $P - O - P$ bonds in cyclic meta-phosphoric acid is three. Moreover, metaphosphoric acid seems to have some hazardous effects, it can cause burns and may cause injuries to the upper respiratory tract and lungs if inhaled.